In our case...
In addition to a formal education/accommodations plan for our daughter, including all of the above mentioned accommodations (lotions in the classroom that are not perscription, water bottle at all times, airconditioning ect..), we have also developed a additional Health Care Plan (not required by school systems) with the school.
This document is referenced in her IEP under accommodations and includes not only the acommondations neccessary for hydration, overheating, skin and wound care but a step by step plan as to what the school staff member is to do in case medical emergency like a fall on the playground resulting in a break in skin or early signs of heat intolerance from playing too hard in gym. Prescribed medications including batriban, hydrocortizone are kept in the nurse's office. At the end of each year the school nurse and I review the document and update as needed. The revised document is distributed to staff members involved in her education (teacher's and therapist). The document is also reviewed and signed by our pediatrician.
The idea of a Health Care Plan (again not required by schools) was not mine, but that of a wonderful nurse administrator in our district that was created by her alone after completing her own independent search on issues related to Ichthyosis. This is my effort in giving credit where credit is due:)
Hope this was helpful,